cc: m.hulme@uea.ac.uk date: Mon, 1 Nov 1999 14:46:53 BST from: "Simon J Shackley" subject: scenario choice to: paula.harrison@ecu.ox.ac.uk, pam.berry@ecu.ox.ac.uk, terry.dawson@ecu.ox.ac.uk, Janet.Sells@bbsrc.ac.uk, eric.audsley@bbsrc.ac.uk, anton.debaets@bbsrc.ac.uk, i.holman@cranfield.ac.uk, tom.downing@ecu.ox.ac.uk, p.loveland@cranfield.ac.uk, r.nicholls@mdx.ac.uk, rounsevell@geog.ucl.ac.be, robert.w.wood@man.ac.uk, t.wilson@mdx.ac.uk dear Colleagues I spoke to Peter Fox at Environment Agency about the scenario issue and he had quite strong views - as indicated in his message below. I'm sure that Peter would welcome any responses. I have also spoken to Sustainability North West who are also in favour of including as many socio-economic scenarios as possible. Richenda at UKCIP is going to contact Merylyn at COP-5 to give us advice from UKCIP. I think we should ask MAFF, DETR and UKWIR about their preferences before the december meeting. (Do you want me to do this Peter?). In response to Mike Hulme's / Paula's proposal, as a non-expert I wasn't sure why it was necessary to test both L and ML and MH and H. Will this really tell us that much mroe than one of those scenarios? Also, I don't think it is so clear that you would not get a Global Sustainability world with the MH or H scenario. It depends on whether the scenarios are about PROCESSES (attempts to achieve sustainability / growth,etc) or the END POINTS (actually achieved sustainability according to a priori definitions, etc.). Using scenarios to think about the processes of reaching different end points / objectives is perhaps more in tune with how political processes work in practice. We can imagine, for example, that a MH level of climate change might be one of the anomalies which would face a world which thinks itself moving towards global sustainability. Of course, we can use the end points definition of scenarios which, by definition, would make MH and H inconsistent with Global sustainability (though uncertainty / surprise could still perhaps disrupt our expectations?). I think it follows less clearly - even for end point definition of scenarios - that the Regional Enterprise world is inconsistent with L or ML. Entreprise in one region is likely to co-exist with lack of enterprise or attempts to achieve sustainability in other regions. Only if you assume that all regions in the world are committed to enterprise, and manage to succeed at being enterprising, can you assume MH or H climate scenarios. That doesn't seem a very plausible future scenario to me. And how different would it be from the global markets scenarios? Yours Simon Message from Peter Fox, Environment Agency Simon, Further to our telephone call I thought I would drop you a note with my views on the need to sample the climate change and socio-economic scenarios for interactions study. I think you have chosen the wrong balance, we should do all 4 socio-economic scenarios with 2 climate change. The overall differences between the four climate change scenarios can be expressed in one dimension: hot, hotter, hottest. Sorry for simplifying this but you understand what I mean. Hence, choosing 2 will allow us to explore and report the range of different responses. However, the socio-economic scenarios express differences in two dimensions, global vs local and stewardship vs economic growth. Dropping even one of these will mean that one or other between-scenario comparisons will not be possible. Also, it seems likely that the socio-economic scenarios will contain the greatest overall variance. This strengthens the need for more scenarios to be included. In my experience of modeling, you need to include more information where variance is greatest. Lastly, if we loose the chance to make climate change a reality to people in the regions we will have missed a major trick in REGIS. The study of socio-economic impacts is critical to success. I'm sorry I cannot advise you on a choice, however, I hope this is helpful. Peter